The present invention relates generally to shock absorbers and levelers of structural agitation. More particularly, it relates to shock absorbers of the type which use both an elastomeric shear spring and flow of fluid through a restricted orifice for absorbing shock, dissipating energy and leveling of support structure such as are commonly used on automobiles and other vehicles. However, it will be appreciated to those skilled in the art that the invention can be readily adapted for use in other environments as, for example, where similar damping and leveling devices are employed to absorb shock and dissipate energy.
Known shock absorbers of the type described include those disclosed in commonly assigned U.S. patent application Ser. No. 950,949, filed Oct. 13, 1978 in the name of L. Dale Coad. In the Coad application an expandible and contractible elastomeric bladder for separating a gas chamber from a fluid chamber in a viscous spring damper was provided for varying the spring rate of the damper, calibrating the damper or leveling a load supported thereby.
Dynamic operating characteristics of prior art self-leveling dampers are chiefly limited to spring rate, damping response, leveling response, cyclical active energy consumption and a dissipation percentage thereof. In prior art devices, dynamic testing has established that such operating characteristics have varied during leveling operations. Such variable dynamic operating characteristics are undesirable, particularly where a high spring rate and low damping response results in a rough ride in a vehicle containing such devices.
In addition, separate vehicle suspension has been needed in conjunction with prior art self-leveling dampers since such prior devices have no load capacity.
The present invention contemplates a new and improved self-leveling viscous spring damper which exhibits improved operating characteristics over prior viscous spring dampers, is self-contained, and can be used as a complete suspension. The invention is simple in design, economical to manufacture, readily adaptable to a plurality of energy dissipation uses and leveling uses, easy to install, easy to remove and provides improved shock absorption and vehicle leveling.